Styryl dyes



Patented Jan. 10, 1950 v Lesliefal. .S. Brooker land FrankL. Whitaltocb ester, :N. X assignors to Eastman Kodakgcoma ,pany, ,Rochest'er, Jersey Y., a ,icorporation ..,ojf jNe'w fNo Drawi-nga Application J1me 3,1946, SeriaLNo. 6141042 can; .1 ans 2 (p--.,dimethy1aminostyryl)benzothiazole ethiodide having the following formula:

c-oH=cH-C N c1nu (32435 \I are=we1l.-known,;-andhavebeen used-as sensitizers of ,-:photographic .,-silver halide emulsions. v ,7 y

We have now found styryl dyes q containing a alkoxyl ror laryloxyl group on the di-methine chain. .Theserdyes :are difierentzfrom the known styryl -.dyes anot only in structure, but adO :not sensitize ,photographic silver halide emulsions appreciably. H .-It .is van object of .our invention toprovide styryl dyes of a newvkind. :Alfurtherobject is to provide a process for preparing such dyes. Other objects will become apparent hereinafter.

In accordance with our 'inventiom'we prepare L- our new styryl dyes-by condensing a p-dialkylaminobenzaldehyde with a cyclammonium quaternary salt "selected from those represented by the following'formula: I

wherein R represents an alkyl group of the formula CnH21L+1 wherein n represents a positive integer, R2 represents a member selected from the ,group consisting of alkyl groups of the formula GJLH27L+1"wher.ein rngrepresents a positive integer, aryl groupsiof .the benzene series.:and aryl groups of the naphthalene series, ,2! represents an anion, and Z represents the non metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of benzoxazole, benzothiazole, benzoselenazole, anaphthoxazole, fl-naphthoxazole, \a-naphthothiazole and B-naphthothiazole nuclei, in the nresenceinf asecondaryamine having sanlionizw ticn-constant1at25 greaterl-than @106, such as piperidine,lz methylpiperidine,letc. 1

Qur -newdyesobtainedby .the foregoing condensa'tion can be represented'by the following general formula:

wherein R, R2, X and Z have the values, given above, and R1 represents an alkyl group of the formula CnH2n+1 wherein n represents a positive integer. e

' That-our new-dyes could be formedinsuch a condensation was not "to be expected, 'based ,on the theory-of "styryl dye "formation discussedby Mills andfRaper, J. Chem. Soc. 127, 2466 (1925), According "to the "theory discussed by Mills and Raper, the:first stage of the process involving condensation of quinaldine ethiodide and -;p dimethylaminobenzaldehyde in the presence of piperi'dine, j is the --formation of a methylene base and' formaticn-of piperidine hydroiodide. This isfollowed "by condensation of the methylene base with the p dimethylaminobenzaldehyde to split outwater and g'ive a condensation :product which reacts with the piperidine hydroiodide to 'givethe'styryl dye.

With the cyclammonium quaternary salts ,which we employ :in practicing our invention (Formula 1; above) one hydrogen vatom would be involved in the initial formation of the methylene base, and there would notrbe. available twohydrogen atoms for the splitting out of water in accordance with the second step postulated by Mills and Raper. Therefore, it would be expected that our new styryl dyes could not be formed by our process, based on the theory discussed by Mills and IRaper. The factthat weihave beenable to obtainour new styryledyes demonstrates that a 1.0 nifierent'theorymustibe employed in thiscase to account for the dye formation.

1 Our condensationsnre advantageously carried, out ;in ra solvent, e. :g. an "alcohol such as ethyl, :nepropyl, isopropyl, n-butyl orisobutyl alcohol. I

'ffllhe followingl'examples :will serve to illustrate :furtherithemanner of obtainin our-new dyes.-

.Elrzxgmple v 1 --1- 2,-ip-dimethylaminowwphenoaqyi styryl) ebenzothiczole methoperchlorate ,1.-2c kg, 261 r-moL-l of .-:2 ph noxymethylhen othiazole and 0.93 g. (1 mol.) of methyl p-toluenew sulfonatewvere 'heated {together at the temperacrude quaternary salt were added0.'75 (1 mol.).

of p-dimethylamino-benzaldehyde, cc. of

ethyl alcohol and 6 drops of piperidine, and the reaction mixture was heated at the refluxing temperature for 4 hours. The hot mixture was treated with a hot solution oi sodium perchlorate 3 g.) in water (50 cc.). Thesolid which separated from the chilled mixture was collected on a filter and washed with water. The residue was stirred, in a beaker, with hot ethyl alcohol and the suspension was chilled. 'The dye was washed on the filter with cold ethyl alcohol; "the yield was 66 per cent crude and 31 per cent, after two recrystallizations from methyl alcohol (340 cc. per gram of dye). The dark green crystals had a melting point of 274- 286 C. with decomposition. 2

Example 2. 2-(p-dimethylamino-a-phenozystyryD-benzothiazole ethoperchlomte .fied in the same manner as the styryl methoperchlorate (Example 1). The yield of dye was 47 per cent crude and24 per cent after two recrystallizations from methyl alcohol. The dark red needles had a melting point of 254256 C. with decomposition.

ExamialeL-Z (p dimethylamino a ethomy styryl) benzothiazole ethdperclzlorate S 00,115 r a A mixture of 1.93 g."(1'mol.) of'Z-ethoxymethylbenzothiazole and 2.00 g'. (1 mol.) of ethyl ptoluenesulfonate were heated together at the temperature of the steam bath'forabout 5'days. To the crude quaternary salt. wereadded 1.49 g. (1 mol.) of p-dimethylaminobenzaldehyde; cc. of ethyl alcohol-and 0115 cc. of piperidine, and the reaction mixture was heated at the refluxing temperature for 4 hours. The hot solution was treated with a hot solution of sodium perchlorate (4g) in water (40 cc.). After chilling, the aqueous layer was decanted and the sticky residue was stirred with three successive portions of cold water. The remaining residue was stirred with hot ethyl acetate, and on long standing at 0 C.,

the solvent evaporated and a crystalline residue was obtained. The yield of dye was 13 per cent crude and 9 per cent after two recrystallizations from 95 per cent ethyl alcohol. The dark blue crystals had a meltin point of 15'7'158 C., with decomposition. a r

f In the manner illustrated above, 2-(p-methoxyphenoxymethyl) benzoxazole-metho p toluenesulfonate,= 2-phenoxyrnethy1 5 phenylbenzoxazole methomethyl'su'lfate, 2 -,ethoxymethylbenzoxazole methomethylsulfate, Z-(m-toloxymethyDbenzothiazole metho-p-toluenesulfonate, 2-(p-chlorophenoxymethy1) benzothiazole methop-toluenesulfonate, 2- (,5 -naphthoxymethyl) benzothiazole metho-p-toluenesulfonate, 2-phenoxymethyl-B-naphthoxazole methomethylsulfate, 2- phenoxymethyl-u-naphthoxazole methomethylsulfate, 2 phenoxymethyl or. benzoselenazole methomethylsulfate, 2 phenoxymethyl-u-naphthothiazole metho p toluenesulfonate and 2- phenoxymethyl B naphthothiazole metho p toluenesulfonate can be condensed with p-dimethylaminobenzaldehyde, p-diethylaminobenzaldehyde and other p dialkylaminobenzaldehydes to give styryl dyes. As shown in the foregoing examples, equimolecular proportions of the cyclammonium quaternary salts and p-dialkylaminobenzaldehyde are satisfactory proportions to employ, and the styryl dyes are advantageously converted to their perchlorate forms to facilitate isolation of the dyes.

The hereindescribed dyes are bleached by photographic developers, such as Eastman Kodak Companys D-76 developer, and are useful as anti-halation and filter dyes in the preparation ofphotographic elements. Theformula for the aforesaid D-76 developer is as follows:

Water, about F cc 750 N-methyl-p-am'inophenol sulfate gram s; 2.0 Sodium sulfite, desiccated do .100.0 Hydroquinone do 5.0 Borax, granular do.. 2.0 Water to make 1iter 1.0

The heterocyclic bases and quaternary salts thereof employed herein are fully described in our copending application Serial No. 519,354, filed January 22, 1944' (now United States Patent 2,478,366, dated. AugustQ, 1949) of which the instant application is a continuation-in-part.

What we claim as our invention and desire to be secured by Letters Patent of the United States is: v

1 The styryl dyes which are" represented by the following general formula: V

' R ,z on, R,

s N' C-JJ=CHC N x \R1 whereiri and R1 each represents an alkyl group of the 'io'rmula CnHa -r wherein n represents a positive integer of'from 1--'to 2, R2 represents an aryl group of the benzene series, and X represents an anion.

3. The styryl dyes which are represented by the following general formula:

wherein R and R1 each represents an alkyl group of the formula CnHzn+1 wherein n represents a positive integer of from 1 to 2 and R2 represents an aryl group of the benzene series.

4. The styryl dye which is represented by the following formula:

5. The styryl dye which is represented by the following formula:

6. The process of preparing a styryl dye comprising condensing a p-dialkylaminobenzaldehyde with a cyclammonium quaternary salt selected from those represented by the following general formula: v

nuclei, in the presence of a secondary amine having an ionization constant at 25 C. greater than 10- '7. The process of preparing a styryl dye comprising condensing a p-dialkylaminobenzaldehyde with a cyclammonium quaternary salt selected from those represented by the following general formula I R ,Z 0R2 wherein R represents an alkyl group of the formula C12H21L+1 wherein n represents a positive integer, Ra represents a member selected from the group consisting of an aryl group of the benzene series and an aryl group of the naphthalene series, X represents an anion, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of benzoxazole, benzothiazole, benzoselenazole, a-naphthoxazole, p-naphthoxazole, a-naphthothiazole and B-naphthothiazole nuclei, in the presence of piperidine.

8. The process of preparing a styryl dye comprising condensing a p-dialkylaminobenzaldehyde in which the alkyl groups are alkyl groups of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 2, with a, cyclammonium quaternary salt selected from those represented by the following formula:

C-JIH,

R/ os m-O-on.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,060,023 Brooker Nov. 10, 1936 2,083,804 Zeh June 15, 1937 2,156,464 Schulz May 2, 1939 2,292,021 Walter Aug. 4, 1942 2,393,743 Brooker Jan. 29, 1946 

1. THE STYRYL DYES WHICH ARE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: WHEREIN R AND R1 EACH REPRESENTS AN ALKYL GROUP OF THE FORMULA CNH2N+1 WHEREIN N REPRESENTS A POSITIVE INTEGER, R2 REPRESENTS A MEMBER SELECTED FROM THE GROUP CONSISTING OF ARYL GROUPS OF THE BENZENE SERIES AND ARYL GROUPS OF THE NAPHTHALENE SERIES, X REPRESENTS AN ANION AND Z REPRESENTS THE NON-METALLIC ATOMS NECESSARY TO COMPLETE A HETEROCYLIC NUCLEUS SELECTED FROM THE GROUP CONSISTING OF BENZOXAZOLE, BENZOTHIASZOLE, BENZOSELENAZOLE, A-NAPHTHOXAZOLE, B-NAPHTHOXAZOLE, A-NAPHTHOTHIAZOLE AND B-NAPHTHOTHIAZOLE NUCLEI. 